• Journal of Korea Multimedia Society
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• v.10 no.8
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• pp.1017-1028
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• 2007

In this paper we propose an effective method to represent, store, and retrieve video streams efficiently from a video database. We extract features from each video frame, normalize the feature values, and represent them as values in the range [0,1]. In this way a video frame with f features can be represented by a point in the f-dimensional space $[0,1]^f$, and thus the video stream is represented by a trail of points in the multidimensional space. The video stream is partitioned into video segments based on camera shots, each of which is represented by a trend vector which encapsulates the moving trend of points in a segment. The video stream query is processed depending on the comparison of those trend vectors. We examine our method using a collection of video streams that are composed of sports, news, documentary, and educational videos. Experimental results show that our trend vector representation reduces a reconstruction error remarkably (average 37%) and the retrieval using a trend vector achieves the high precision (average 2.1 times) while maintaining the similar response time and recall rate as existing methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.304-309
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• 2004

Recently, the needs for multimedia stream such as digital audio and video in the Internet has increased tremendously. Unlike TCP, the UDP protocol, which has been used to transmit streaming traffic thorough the Internet, does not apply any congestion control mechanism to regulate the data flow thorough the shared network And it leads to congestion collapse of the Internet and results in long-term transmission delay. To avoid any adverse effect on the current Internet functionality, a now protocol of modification or addition of some functionality to perform congestion control and to reduce huge transmission delay in transmitting of multimedia stream are in study. TCP-friendly congestion control mechanism is classified into two : one is window-based congestion control scheme using general window management functionalities, the other is rate-based congestion control scheme using TCP modeling equation. In this paper, we propose an algorithm for improving the transmitting rate on a hybrid TCP-friendly congestion control scheme combined with widow-based and late-based congestion control for multimedia stream. And we also simulate the performance of improved TEAR implementation using NS. With He simulation results, we show that the improved TEAR can provide better fairness and lower rate fluctuations than TCP.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.95-101
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• 2005

In this paper, some performance characteristics of multimedia traffic for mobile ad-hoc networks is studied with simulations. Synthetic streaming video is considered as the multimedia traffic for MPEG-coded video in the simulation. The synthetic video stream is generated with a video stream generation algorithm. The algorithm generate VBR traffics for MPEG video streams with special predefined GOP(group of pictures) patterns that is consisted of a sequence of I(intra-coded), P(predicted-coded) and B(bidirectional-coded) frames. The synthetic VBR streams is transmitted through UDP protocol with on-demand mobile ad-hoc network routing protocols like as AODV and DSR. And performances for video streams through mobile ad-hoc networks is evaluated, the throughputs is compared between data and video traffics.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.587-596
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• 2004

During recent years, a new framework, which aims to bring a unified and global approach in indexing, browsing and querying various digital multimedia data such as audio, video and image has been developed. This new system partitions each media stream into smaller units based on actual physical events. These physical events within oath media stream can then be effectively indexed for retrieval. In this paper, we present a new approach that exploits audio, image and video features to segment and analyze the audio-visual data. Integration of audio and visual analysis can overcome the weakness of previous approach that was based on the image or video analysis only. We Implement a web-based multi media data retrieval system called XCRAB and report on its experiment result.

• The Journal of the Acoustical Society of Korea
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• v.24 no.4
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• pp.186-193
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• 2005

The Terrestrial Digital Multimedia Broadcasting (T-DMB) system supplies high quality audio comparable with VCD in 7 inch display and high quality audio comparable CD at the mobile reception environment T-DMB will launch commercial service at the middle of 2005. However the bandwidth for audio data and the number of channels are restricted to 128 kbps and 2 respectively in the current T-DMB standard because of the limitation of available bandwidth for multimedia data. This Paper Proposes a novel media processor structure for providing multi-channel audio contents oyer T-DMB system allowing backward compatibility with the legacy T-DMB receiver. Furthermore. we also Propose an adaptive receiver structure to supply optimal audio contents on various speaker configuration in T-DMB receiver. To provide multi-channel audio contents allowing backward comaptilbity with the legacy T-DMB receiver, the additional data for multi-channel audio are defined as a dependent stream of main audio stream. The OD strucure for control an additional multi-channel audio elementary stream is proposed without changing the BIFS of the legacy T-DMB system.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.

• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1767-1777
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• 2010

In digital TV broadcasting, such as terrestrial, cable, satellite, and IPTV, the head-end of digital TV broadcasting has a more complicated transmission structure than that of analog TV broadcasting. Furthermore, digital TV broadcasting has a feature that supports multiplex models, such as Multiple Program Transport Stream (MPTS). Therefore, the purpose of our work was to design and examine a more efficient new system of emergency alert message transmission to support the digital TV broadcasting environments. Digital TV broadcasting is the IP generation or RF transmission of 8-VSB, QAM, and QPSK modulated through a multiplexer or re-multiplexer multiplexed stream as a MPEG-2 Transport Stream after content encoding. The new system proposed in this paper transmits an emergency alert message without scrambling after replacing the PID and payload of the -packet with the message prototype in the TS stream from the multiplexer. If we need to transmit an emergency alert message under digital TV broadcasting services, then the receiver first checks the PID of each packet in the TS stream for the emergency alert message. Next, if a packet is determined to be an emergency alert message, then the set-top box displays the message on the TV screen using its function of On Screen Display, or the PC based software displays the message on the monitor screen using its function of overlay with user interface if the packet is found to be an emergency alert message. We have designed an emergency alert message protocol and a system model. By experiments and analysis of the system, we concluded that the system achieved efficiency and the ability to send and receive emergency alert messages using the system under different digital TV broadcasting service environments.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1242-1251
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• 2009

A DSMS(Data Stream Management System) in ubiquitous environment processes huge data that input from a number of sensor. The existed system is used with a load shedding method that is eliminated with a part of huge data stream when it doesn't process the huge data stream. The Load shedding method has to filter a part of input data. This is because, data completeness or reliability is decreased. In this paper, we proposed the overload prediction load balancing to maintain data completeness when the system has an overload. The proposed method predicts the overload time. and than it is decreased with data loss when achieves the prediction overload time. The performance evaluation shows that the proposed method performs better than the existed method.

• Journal of Korea Multimedia Society
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• v.16 no.12
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• pp.1427-1438
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• 2013

We have developed a 128-bit stream cipher algorithm composed of the 5-stage pipeline, capable of real-time processing, confidentiality and integrity. The developed stream cipher is a stream cipher algorithm that makes the final 128-bit ciphers through a whitening process after making the ASR 277 bit and SHACAL-2 and applying them to the CFB mode. We have verified the hardware performance of the proposed stream cipher algorithm with Modelsim 6.5d and Quartus II 12.0, and the result shows that the hardware runs at 33.34Mhz(4.27Gbps) at worst case. According to the result, the new cipher algorithm has fully satisfied the speed requirement of wireless Internet and sensor networks, and DRM environment. Therefore, the proposed algorithm with satisfaction of both confidentiality and integrity provides a very useful ideas.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.44-52
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• 1994

When a constructed multimedia application system transfers a various media of which quality of service is different, a previously constituted synchronization at source site generates the synchronization anomaly that the synchronization relation is broken by a delay or a data loss at destination. To solve the synchronization anomaly, we propose the “Multimedia synchronization scenario method : MSSM” which defines as one(1) event all objects generated at multimedia application and creates the optimal scenario of multimedia presentation under temporal constraints. The characteristics of MSSM can minimize the delay effect, guarantee the media stream continuity for preventing the media stretch, and provide the synchronization information to a user and/or a system. After deciding a synchronization possibility. MSSM confirm user its information. If there is a synchronization possibility. MSSM products optimal multimedia presentation scenario, and can present multimedia adaptively.